1993 Nissan Altima Studders When Accelerating

The car is a 1993 Nissan Altima. When I first start the gas, the exhaust will sometimes smell a little like gasoline. What it does is that when I start accelerating from a stop, the engine will jerk suddenly become unresponsive and kind of "choke" until I release the gas pedal and re-accelerate a little harder. It does it when just cruising, on the freeway for example. To me it feels like a problem stemming from the engine. There are no unusual noises. It seems to do it more when the engine is cold as opposed to when I've been driving it for a while. It started doing it the day after I changed the air filter, and I didn't disconnect any components when I did that, although I had been driving it around for quite a while on an extremely hot day. I'm lost as to what it could be?